Increasing the stability of cooling reservoirs’ operation by using selective water intake schemes

Abstract

Introduction. The paper addresses issues of increasing the stability of cooling reservoirs’ operation at large power plants during periods when extremely high air temperatures occur. These periods are usually very short and last no more than 10 days. As a rule, the water temperature distribution by depth in cooling reservoirs is substantially inhomogeneous: under the surface layer, which is the warmest, there is a near-bottom layer, which is significantly colder. In this regard, during the periods characterized by extreme temperatures, it is proposed to perform selective water intake from the cold nearbottom layers. The authors analyze the hydrodynamic aspects of such a water supply scheme through the example of a cooling reservoir at the Magnitogorsk Iron and Steel Works (MMK PJSC). Methods. Given that it is crucial to consider and analyze the vertical structure of the studied temperature fields, the problem was solved in a three-dimensional setting in a non-hydrostatic approximation. Computational experiments were performed using the ANSYS Fluent package. Results. The authors studied the formation of thermal fields in the cooling reservoir both during the normal operation of the cooling system and in the emergency mode, i.e. at extremely high air temperatures. As one of the measures to ensure the uninterrupted, stable operation of the cooling system under extreme weather conditions, it was proposed to perform selective water intake from the bottom level of the cooling reservoir by deepening the cut-off panels. Conclusions. The proposed scheme of selective water intake from the lower levels of the cooling reservoir makes it possible to ensure the stability of cooling system operation during periods when extremely high air temperatures occur, which last up to 10 days.